Motion sensors stop to send motion to the shelly app after about a hour

Hello everybody.
I just bought 3 Shelly Motion sensors.
The problem I'm having is that, once they have been installed for the first time or rebooted them, the Shelly application correctly receives that there has been a movements. It all works for half an hour or so. After this time the application no longer receives that there have been movements, and this happens for all three sensors. So this is not a defect of a single sensor.
The strange thing is that if I access the web interface (via IP) of the individual sensors I can clearly see that movement is detected from there! But it is no longer communicated to the Shelly application .....
I have tried everything. I also downgraded the firmware from the latest version. The only thing that makes them communicate the movement to the application (and therefore also to the Alexa routines) is to restart them, so for that half hour the movements are correctly communicated to the application (and to the Alexa routines) and after nothing more, the movements can be viewed through the web interface (so they are still detected) of the sensor but they are no longer communicated....
Obviously the sensors IPs are fixed.
I tried everything ..... any suggestion abuot this?

Thank you so much
I tried firmware 1.1.0 too but no results... with new beta firmware it seems to do the trick but after some hours of "illusion" the motion sensors started again to not send.
What do you use instead the app?

BTW now I have a new problem, I hard reset the three sensors but only one can be included as device in the app. The other two are correctly detected but give error when the app is trying to connect to the cloud for inclusion.... I saw a strange thing, the device that wouldn't include has a certain ID in the device info and in the name of the wifi sid, but when it is recognized by the app the ID is different! I think that is for this that it can't be included when the cloud is contacted... How it can be?

Can you help me about this or I must open another thread for this other probem?
Thank you !